153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Test triggering of loading of firmware from different mount
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* namespaces. Expect firmware to be always loaded from the mount
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* namespace of PID 1. */
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <sched.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#ifndef CLONE_NEWNS
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# define CLONE_NEWNS 0x00020000
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#endif
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static char *fw_path = NULL;
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static void die(char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vfprintf(stderr, fmt, ap);
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va_end(ap);
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if (fw_path)
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unlink(fw_path);
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umount("/lib/firmware");
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exit(EXIT_FAILURE);
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}
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static void trigger_fw(const char *fw_name, const char *sys_path)
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{
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int fd;
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fd = open(sys_path, O_WRONLY);
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if (fd < 0)
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die("open failed: %s\n",
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strerror(errno));
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if (write(fd, fw_name, strlen(fw_name)) != strlen(fw_name))
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exit(EXIT_FAILURE);
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close(fd);
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}
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static void setup_fw(const char *fw_path)
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{
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int fd;
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const char fw[] = "ABCD0123";
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fd = open(fw_path, O_WRONLY | O_CREAT, 0600);
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if (fd < 0)
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die("open failed: %s\n",
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strerror(errno));
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if (write(fd, fw, sizeof(fw) -1) != sizeof(fw) -1)
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die("write failed: %s\n",
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strerror(errno));
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close(fd);
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}
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static bool test_fw_in_ns(const char *fw_name, const char *sys_path, bool block_fw_in_parent_ns)
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{
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pid_t child;
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if (block_fw_in_parent_ns)
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if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
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die("blocking firmware in parent ns failed\n");
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child = fork();
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if (child == -1) {
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die("fork failed: %s\n",
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strerror(errno));
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}
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if (child != 0) { /* parent */
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pid_t pid;
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int status;
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pid = waitpid(child, &status, 0);
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if (pid == -1) {
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die("waitpid failed: %s\n",
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strerror(errno));
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}
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if (pid != child) {
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die("waited for %d got %d\n",
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child, pid);
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}
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if (!WIFEXITED(status)) {
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die("child did not terminate cleanly\n");
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}
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if (block_fw_in_parent_ns)
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umount("/lib/firmware");
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return WEXITSTATUS(status) == EXIT_SUCCESS;
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}
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if (unshare(CLONE_NEWNS) != 0) {
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die("unshare(CLONE_NEWNS) failed: %s\n",
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strerror(errno));
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}
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if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) == -1)
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die("remount root in child ns failed\n");
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if (!block_fw_in_parent_ns) {
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if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
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die("blocking firmware in child ns failed\n");
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} else
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umount("/lib/firmware");
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trigger_fw(fw_name, sys_path);
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exit(EXIT_SUCCESS);
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}
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int main(int argc, char **argv)
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{
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const char *fw_name = "test-firmware.bin";
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char *sys_path;
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if (argc != 2)
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die("usage: %s sys_path\n", argv[0]);
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/* Mount tmpfs to /lib/firmware so we don't have to assume
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that it is writable for us.*/
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if (mount("test", "/lib/firmware", "tmpfs", 0, NULL) == -1)
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die("mounting tmpfs to /lib/firmware failed\n");
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sys_path = argv[1];
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if (asprintf(&fw_path, "/lib/firmware/%s", fw_name) < 0)
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die("error: failed to build full fw_path\n");
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setup_fw(fw_path);
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setvbuf(stdout, NULL, _IONBF, 0);
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/* Positive case: firmware in PID1 mount namespace */
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printf("Testing with firmware in parent namespace (assumed to be same file system as PID1)\n");
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if (!test_fw_in_ns(fw_name, sys_path, false))
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die("error: failed to access firmware\n");
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/* Negative case: firmware in child mount namespace, expected to fail */
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printf("Testing with firmware in child namespace\n");
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if (test_fw_in_ns(fw_name, sys_path, true))
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die("error: firmware access did not fail\n");
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unlink(fw_path);
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free(fw_path);
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umount("/lib/firmware");
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exit(EXIT_SUCCESS);
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}
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